A person holds up images of Venezuela’s President Hugo, right, and Venezuela’s independence hero Simon Bolivar as people gather to pray for Chavez at Simon Bolivar square in Caracas, Venezuela, Tuesday.

CARACAS, Venezuela — Venezuela’s vice president said Wednesday that President Hugo Chavez will face a “complex and hard” process after undergoing his fourth cancer-related operation in Cuba.

Vice President Nicolas Maduro made the announcement a day after Chavez’s surgery, appearing on television with a sad expression, alongside other top allies of the president.

“It was a complex, difficult, delicate operation,” Maduro said, indicating “the post-operative process is also going to be a complex and hard process.”

The vice president, whom Chavez named over the weekend as his chosen political heir, was flanked by National Assembly President Diosdado Cabello and Oil Minister Rafael Ramirez, who had accompanied the president in Havana during the surgery.

Maduro said Cabello and Ramirez had returned to Caracas about 3 a.m. and that they had talked about the situation until daybreak. Maduro’s voice was hoarse and cracked at times.

Without giving details, Maduro reiterated Chavez’s recent remarks that the surgery presented risks and that people should be prepared for any “difficult scenarios, which can be faced only with the unity of the people.” Still, Maduro expressed optimism Chavez would return home.

“We’re more united than ever,” Maduro said, while Cabello and Ramirez stood solemnly. “We’re united in loyalty to Chavez.”

The vice president criticized the opposition, accusing it of using Chavez’s illness to attack him. Some political adversaries have said the president should be more forthcoming about details of his pelvic cancer.

Maduro had said on Tuesday night that the operation concluded successfully after more than six hours and that Chavez was to begin “special treatments,” which he didn’t specify. Chavez’s children and grandchildren accompanied him in Havana during the surgery, the vice president said.

The morning after Chavez’s operation, Venezuelan state television showed a Mass where the president’s supporters prayed for him.

Chavez announced over the weekend that he needed to have surgery again after tests showed “some malignant cells” had reappeared in the same area of his pelvic region where tumors were previously removed.

He also said on Saturday for the first time that if illness cuts short his presidency, Maduro should take his place and be elected president to continue on with his socialist movement.

The 58-year-old president won re-election in October and is due to be sworn in for a new six-year term on Jan. 10. If Chavez were to die, the constitution says that new elections should be called and held within 30 days.

Throughout his nearly 14-year-old presidency, Chavez has been loved by some Venezuelans and reviled by others as he has nationalized companies, crusaded against U.S. influence and labeled his enemies “oligarchs” and “squalid ones.”

On the streets of Caracas this week, Venezuelans on both sides of the country’s deep political divide voiced concerns about Chavez’s condition and what might happen if he doesn’t survive.

Some Chavez supporters said they find it hard to think about losing the president and are worried about the future.

Others Venezuelans said that while they’re sorry about Chavez’s health and wish him the best, it isn’t a particular concern for them. Many were out buying Christmas gifts and food as they prepared for the holiday season.

“The truth is that I have not paid much attention to the news. I just know the president is very sick and he went to Cuba for an operation,” said Gabriela Hernandez, a nurse and opposition supporter. “I hope that he can get better. ... I don’t wish for misfortune for anybody.”

Some also expressed concern about the possibility of political upheaval if Chavez doesn’t survive.

“Many people don’t dare to say it, but they want Chavez’s death,” said Omar Mendez, a shopkeeper who said he doesn’t support Chavez or the opposition. “I would say something to those people: They should think hard about the consequences if Chavez does not survive this terrible illness because Chavez’s death could bring about an unprecedented political crisis.”

Analysts say Maduro could eventually face challenges in trying to hold together the president’s diverse “Chavismo” movement, which includes groups from radical leftists to moderates, as well as military factions.

Maduro is considered to be a member of radical left wing of Chavez’s movement that is closely aligned with Cuba’s communist government.

Chavez first announced he had been diagnosed with cancer in June 2011. He underwent a surgery for a pelvic abscess, and then had a baseball-sized tumor removed. In February, he underwent another surgery when a tumor reappeared in the same area.

He has also undergone months of chemotherapy and radiation treatments. Throughout his treatments in Cuba, Chavez has kept secret some details of his illness, including the exact location and type of the tumors.